Diacrylates and dimethacrylates

ABSTRACT

Compounds of formulae (Ia) and (Ib)                    
     wherein the substituents R 1  are each independently of the other hydrogen or methyl, R 2  is an unsubstituted C 1 -C 20 alkyl group or a C 1 -C 20 alkyl group which is substituted by one or more than one substituent selected from the group consisting of hydroxy, C 6 -C 14 aryl and halogen, an unsubstituted phenyl group or a phenyl group which is substituted by one or more than one substituent selected from the group consisting of C 1 -C 6 alkyl, hydroxy or halogen, or is a radical of formula —CH 2 —OR 3 , wherein R 3  is an unsubstituted C 1 -C 20 alkyl group or a C 1 -C 20 alkyl group which is substituted by one or more than one substituent selected from the group consisting of hydroxy, C 6 -C 14 aryl and halogen, an unsubstituted phenyl group or a phenyl group which is substituted by one or more than one substituent selected from the group consisting of C 1 -C 6 alkyl, hydroxy and halogen, or is a C 2 -C 6 alkenyl group, a C 2 -C 20 acyl group or an unsubstituted cyclohexylcarbonyl group or a cyclohexylcarbonyl group which is substituted by one or more than one substituent selected from the group consisting of C 1 -C 6 alkyl, hydroxy and halogen, Z is a group of formulae (IIa)-(IIe)                    
     wherein Y is a direct bond, C 1 -C 6 alkylene, —S, —O—, —SO—, —SO 2 — or —CO—, and R 1  is hydrogen or methyl, and wherein the aromatic and cycloaliphatic rings of formulae (IIa)-(IIe) are unsubstituted or substituted by one or more than one substituent selected from the group consisting of C 1 -C 6 alkyl, chloro and bromo, form, in conjunction with other acrylates or methacrylates, low viscosity photocurable compositions which, when fully cured, give moulded articles of excellent flexibility.

This is a divisional of application Ser. No. 08/342,955, now U.S. Pat.No. 6,043,323, filed on Nov. 21, 1994, which is a continuation of Ser.No. 08/006,444 filed Jan. 21, 1993, abandoned.

The present invention relates to novel acrylates and methacrylates, tophotosensitive compositions containing these compounds and to a processfor the preparation of three-dimensional objects from saidphotosensitive compositions.

Radiation-sensitive liquid resins or resin systems can be used for avariety of utilities, typically as coating compositions, adhesives orphotoresists. Quite generally, liquid resins or resin systems shouldalso be suitable for fabricating three-dimensional objects by thestereolithographic technique described in U.S. Pat. No. 4,575,330; butmany resins prove to be too viscous, whereas others are insufficientlylight sensitive or suffer too severe shrinkage during the cure. Thestrength properties of the moulded articles or objects made fromphotocured resins are also often unsatisfactory.

Liquid resin systems for stereolithography comprising different mono-and diacrylates and mono- and dimethacrylates as well as a urethaneacrylate or methacrylate and a monomeric or oligomeric diacrylate ormethacrylate derived from bisphenol A or bisphenol F are disclosed inEP-A 425 441. When precured with laser light, these systems give greenstages of superior green strength and, after the full cure,rigid-elastic objects whose flexibility is, however, insufficient forcertain utilities.

EP-A 506 616 discloses liquid resin compositions of several acrylatesand/or methacrylates which contain further hydroxyl group containingaliphatic or cycloaliphatic acrylates and/or methacrylates. The curedmoulded articles made from these compositions by stereolithography havesuperior flexibility and tear propagation strength. A drawback of thesecompositions for processing in mechanical apparatus, however, is theirrather high viscosity.

It has now been found possible to prepare novel hydroxyl groupcontaining acrylates and methacrylates which, in conjunction with otheracrylates or methacrylates, form low viscosity photocurable compositionswhich, when fully cured, give moulded articles of excellent flexibility.

Accordingly, the invention relates to compounds of formulae (Ia) and(Ib)

wherein the substituents R₁ are each independently of the other hydrogenor methyl, R₂ is an unsubstituted C₁-C₂₀alkyl group or a C₁-C₂₀alkylgroup which is substituted by one or more than one substituent selectedfrom the group consisting of hydroxy, C₆-C₁₄aryl and halogen, anunsubstituted phenyl group or a phenyl group which is substituted by oneor more than one substituent selected from the group consisting ofC₁-C₆alkyl, hydroxy or halogen, or is a radical of formula —CH₂—OR₃,wherein R₃ is an unsubstituted C₁-C₂₀alkyl group or a C₁-C₂₀alkyl groupwhich is substituted by one or more than one substituent selected fromthe group consisting of hydroxy, C₆-C₁₄aryl and halogen, anunsubstituted phenyl group or a phenyl group which is substituted by oneor more than one substituent selected from the group consisting ofC₁-C₆alkyl, hydroxy and halogen, or is a C₂-C₆alkenyl group, aC₂-C₂₀acyl group or an unsubstituted cyclohexylcarbonyl group or acyclohexylcarbonyl group which is substituted by one or more than onesubstituent selected from the group consisting of C₁-C₆alkyl, hydroxyand halogen, Z is a group of formulae (IIa)-(IIe)

wherein Y is a direct bond, C₁-C₆alkylene, —S—, —O—, —SO—, —SO₂— or—CO—, and R₁ is hydrogen or methyl, and wherein the aromatic andcycloaliphatic rings of formulae (IIa)-(IIe) are unsubstituted orsubstituted by one or more than one substituent selected from the groupconsisting of C₁-C₆alkyl, chloro and bromo.

R₂ or R₃ as C₁-C₂₀alkyl may be branched or, preferably, straight-chainalkyl. Typical examples of such alkyl groups are methyl, ethyl,n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl,neo-pentyl, n-hexyl, octyl, decyl, dodecyl and icosyl.

The alkyl groups may also be substituted by one or more than onesubstituent selected from the group consisting of hydroxy, C₆-C₁₄aryland halogen. Typical examples of substituted alkyl groups arehydroxymethyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-chloropropyl,2,3-dichlorobutyl, 2-phenylethyl and 2,3-diphenylbutyl.

R₃ as C₂-C₆alkenyl may be branched or, preferably, straight-chainalkenyl. Typical examples of alkenyl groups are vinyl, prop-1-enyl,prop-2-enyl, 2-methylprop-2-enyl, n-but-3-enyl, n-pent-4enyl andn-hex-5-enyl. Alkenyl groups containing two or three carbon atoms arepreferred, and vinyl, prop-l-enyl and prop-2-enyl are especiallypreferred.

Typical examples of C₂-C₂₀acyl groups are acetyl, propionyl, n-butyryl,isobutyryl, pivaloyl, hexyloyl, octyloyl, tetradecyloyl, hexadecyloyland octadecyloyl.

R₃ as phenyl or cyclohexylcarbonyl may be unsubstituted or substitutedby one or more than one substituent selected from the group consistingof C₁-C₆alkyl, hydroxy and halogen. Typical examples of such groups aretolyl, xylyl, mesityl, 2-hydroxyphenyl, 4hydroxyphenyl, 2-chlorophenyl,4-chlorophenyl, 3,5-dichlorophenyl, 2,4-dichlorophenyl,2,6-dimethylcyclohexylcarbonyl, 4hydroxycyclohexylcarbonyl,p-hydroxybenzyl, p-chlorobenzyl and o-ethylbenzyl.

The aromatic and cycloaliphatic rings in formulae (IIa)-(IIe) arepreferably unsubstituted.

In the compounds of formulae (Ia) and (Ib) R₂ is preferably C₁-C₂₀alkyl,phenyl, C₁-C₂₀alkoxymethyl, phenoxymethyl orcyclohexylcarbonyloxymethyl.

Especially preferred compounds of formulae (Ia) and (Ib) are thosewherein R₂ is n-butyl, phenyl, n-butoxymethyl, phenoxymethyl orcyclohexylcarbonyloxymethyl.

The most preferred meaning of R₂ is n-butoxymethyl.

Z in formulae (Ia) and (Ib) is preferably a group of formula (IIc) or(IIe).

Compounds of formulae (Ia) and (Ib) are especially preferred wherein Zis

The compounds of formulae (Ia) and (Ib) can be prepared by per se knownprocesses. A further object of the invention is a process for thepreparation of compounds of formulae (Ia) and (Ib), which comprisesreacting a diglycidyl ether of formula (III)

wherein R₂ and Z have the above meanings, in a manner known per se, withacrylic or methacrylic acid.

The diglycidyl compounds of formula (III) are known and disclosed, interalia, in EP-A 22 073.

The reaction of the diglycidyl compounds of formula (III) with acrylicor methacrylic acid normally gives a mixture of compounds (Ia) and (Ib),compound (Ia) being the main product and compound (Ib) being obtained incomparatively minor amounts (c. 10-20 %). Separation of the twostructurally isomeric compounds for use in photosensitive compositionsis not necessary.

Illustrative specific examples of the diglycidyl compounds of formula(III) are:

2,2-bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(3-methoxy-2-glycidyloxypropoxy)phenylpropane,

2,2-bis[p-(3-ethoxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(3-dodecyloxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(3-tetradecyloxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(3-benzyloxy-2-glycidyloxypropoxy)phenyl]propane,

bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]methane,

1,3-bis[p-(3-phenoxy-2-glycidyloxypropoxy]benzene,

bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]sulfone,

2,2-bis[p-(3-cyclohexoxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)-3,5-dibromophenyl]propane,

2,2-bis[p-(3-allyloxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(3-phenoxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)cyclohexyl]propane,

2,2-bis[p-(3-cyclohexylcarbonyloxy-2-glycidyloxypropoxy)phenyl]propane,

2,2-bis[p-(2-glycidyloxyhexoxy)phenyl]propane, and

2,2-bis[p-(2-phenyl-2-glycidyloxyethoxy)phenyl]propane.

A further object of the invention is a photosensitive compositioncomprising

(a) 5-65 % by weight of a compound of formula (Ia) or (Ib) according toclaim 1,

(b) 15-70 % by weight of one or more than one bifunctional acrylate ormethacrylate having a molecular weight in the range from 150 to 450 anddiffering from compound of formula (Ia) or (Ib),

(c) 0-40 % by weight of one or more than one monomeric polyfunctionalacrylate or methacrylate having a functionality of not less than 3 and amolecular weight of not more than 600,

(d) 0-10 % by weight of at least one monofunctional acrylate ormethacrylate,

(e) 0-10 % by weight of N-vinylpyrrolidone or N-vinylcaprolactam,

(f) 2-10 % by weight of at least one photoinitiator, and

(g) 0-60 % by weight of at least one urethane acrylate or methacrylatehaving a functionality of 2-4 and a molecular weight in the range from500-10 000, such that the sum of the amounts of components (a) to (g)together is 100% by weight

Compounds useful as component (b) include the diacrylate anddimethacrylate esters of aliphatic, cycloaliphatic or aromatic diols,including 1,3- or 1,4-butanediol, neopentyl glycol, 1,6-hexanediol,diethylene glycol, triethylene glycol, tetraethylene glycol,polyethylene glycol, tripropylene glycol, ethoxylated or propoxylatedneopentyl glycol, 1,4-dihydroxymethylcyclohexane,2,2-bis(4-hydroxycyclohexyl)propane, bis(4-hydroxycyclohexyl)methane,hydroquinone, 4,4′-dihydroxybiphenyl, bisphenol A, bisphenol F,bisphenol S, ethoxylated or propoxylated bisphenol A, ethoxylated orpropoxylated bisphenol F or ethoxylated or propoxylated bisphenol S.

Such diacrylates and dimethacrylates are known and some are commerciallyavailable, typically those sold by the SARTOMER Company under theproduct names SR 348 for the dimethacrylate of ethoxylated bisphenol A,SR 349 for the diacrylate of ethoxylated bisphenol A, SR 247 forneopentyl glycol diacrylate and SR 344 for polyethylene glycol 400diacrylate.

It is preferred to use a diacrylate or dimethacrylate of ethoxylatedbisphenol A as component (b).

Compounds useful as component (c) are typically triacrylates ortrimethacrylates of formula (IV) or (V)

R₄—CH₂—CCH₂—R₅)₃  (IV),

R₅—CHCH₂—R₅)₂  (V),

wherein R₄ is hydrogen, methyl or hydroxyl, and R₅ is a radical offormula (VI)

wherein n is 0 or a number from 1-3 and R₆ and R₇ are each independentlyof the other hydrogen or methyl.

Among the compounds of formulae (IV) and (V), those compounds of formula(IV) are especially preferred in which R₄ is methyl and R₅ is a radicalof formula (VI), wherein n is 0.

Illustrative examples of compounds which may be used as component (c)are: 1,1,1-trimethylolpropane triacrylate or methacrylate, ethoxylatedor propoxylated 1,1,1-trimethylolpropane triacrylate or methacrylate,ethoxylated or propoxylated glycerol triacrylate, pentaerythritolmonohydroxy triacrylate or methacrylate; and also higher functionalacrylates or methacrylates such as dipentaerythritol monohydroxypentaacrylate or bis(trimethylolpropane) tetraacrylate. Such compoundsare known to the skilled person and some are commercially available.

Preferably the compounds useful as component (c) have a molecular weightin the range from 250 to 700.

It is especially preferred to use trimethylolpropane triacrylate andtrimethylolpropane trimethacrylate as component (c).

Component (d) of the novel compositions may be selected from thefollowing compounds: allyl acrylate, allyl methacrylate, methyl(meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl(meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate,2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl(meth)acrylate and n-dodecyl (meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2- and 3-hydroxypropyl (meth)acrylate, 2-methoxyethyl(meth)acrylate, 2-ethoxyethyl (meth)acrylate and 2- or 3-ethoxypropyl(meth)acrylate, tetrahydrofurfurylmethacrylate,2-(2-ethoxyethoxy)ethylacrylate, cyclohexyl methacrylate, 2-phenoxyethylacrylate, glycidyl acrylate and isodecyl acrylate. Such products arealso known and some are commercially available, as from SARTOMER

2-Phenoxyethylacrylate is especially preferred.

The novel compositions may contain up to 10% by weight ofN-vinylpyrrolidone or N-vinylcaprolactam or a mixture thereof ascomponent (e). It is preferred to use N-vinylpyrrolidone.

Any type of photoinitiator which, when irradiated suitably, forms freeradicals can be employed as component (f) in the novel compositions.Typical known photoinitiators are benzoins, benzoin ethers, includingbenzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropylether, benzoin phenyl ether and benzoin acetate; acetophenones,including acetophenone, 2,2-dimethoxyacetophenone and1,1-dichloroacetophenone; benzil, benzil ketals such as benzil dimethylketal and benzil diethyl ketal; anthraquinones, including2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone,1-chloroanthraquinone and 2-amylanthraquinone; triphenylphosphine;benzoylphosphine oxides, for example2,4,6-trimethylbenzoyldiphenylphosphine oxide (Luzirin TPO);benzophenones such as benzophenone and4,4′-bis(N,N′-dimethylamino)benzophenone; thioxanthones and xanthones;acridine derivatives; phenazine derivatives; quinoxaline derivatives or1-phenyl-1,2-propanedione; 2-0-benzoyl oxime; 1-aminophenyl ketones or1-hydroxyphenyl ketones such as 1-hydroxycyclohexyl phenyl ketone,phenyl 1-hydroxyisopropyl ketone and 4-isopropylphenyl1-hydroxyisopropyl ketone.

Suitable initiators are also are electron transfer initiators of thexanthone type, for example2,4,5,7-tetraiodo-6hydroxy-9-cyano-3H-xanthen-3-one which, together withsuitable electron donors, have a high reactivity in the visible range ofthe spectrum.

Another class of suitable photoinitiators (f) comprises the ionicdye-counter ion compounds which are capable of absorbing actinicradiation and generating free radicals which initiate the polymerisationof the acrylates (a) to (d) and optionally (g). The compositions of theinvention containing ionic dye-counter ion compounds can be cured morevariably in this way with visible light within the adjustable wavelengthrange of 400-700 nm. Ionic dye-counter ion compounds and their mode ofaction are known, for example from EP-A-0 223 587 and U.S. Pat. Nos.4,751,102; 4,772,530 and 4,772,541. Typical examples of suitable ionicdye-counter ion compounds are the anionic dye-iodonium ion complexes,the anionic dye-pyrylium ion complexes and, especially, the cationicdye-borate anion compounds of formula

wherein X⁺ is a cationic dye and R₈, R₉, R₁₀ and R₁₁, are eachindependently of one another an alkyl, aryl, alkaryl, allyl, aralkyl,alkenyl or alkynyl group, or an alicyclic or saturated or unsaturatedheterocyclic group.

Particularly suitable photoinitiators which are normally used inconjunction with a HeCd laser as source of irradiation are acetophenonessuch as 2,2-dialkoxybenzophenones, and α-hydroxyphenylketones, typically1-hydroxycyclohexylphenyl ketone or (2-hydroxyisopropyl)phenyl ketone(=2-hydroxy-2,2dimethylacetophenone).

A particularly preferred photoinitiator is 1-hydroxycyclohexylphenylketone.

The novel compositions may also contain other photoinitiators ofdifferent sensitivity to radiation of emission lines of differentwavelengths. The inclusion of such photoinitiators effects the betterutilisation of a UV/VIS light source which radiates emission lines ofdifferent wavelength. It is advantageous to choose these otherphotoinitiators and to use them in such a concentration that a uniformoptical absorption is produced with respect to the emission lines used.

The urethane acrylates used in the novel compositions as component (g)are known to those skilled in the art and can be prepared in knownmanner, typically by reacting a hydroxyl-terminated polyurethane withacrylic acid or methacrylic acid to the corresponding urethane acrylate,or by reacting an isocyanate-terminated prepolymer with hydroxyalkylacrylates or methacrylates to the urethane acrylate. Suitable processesare disclosed, inter alia, in EP-A 114 982 and EP-A 133 908. Themolecular weight of such acrylates is generally in the range from 400 to10 000, preferably from 500 to 7000. Urethane acrylates are alsocommercially available and are sold by UCB under the registeredtrademark EBECRYL®, by Morton Thiokol under the registered trademarkUvithane® or by the SARTOMER Company under the product names SR 9504, SR9600, SR 9610, SR 9620, SR 9630, SR 9640 and SR 9650.

It is preferred to use those urethane acrylates with have a molecularweight from 500-7000 and which are prepared preferably from aliphaticeducts.

The novel photosensitive compositions can be polymerised by irradiationwith actinic light, typically with electron beams, X-rays, UV or VISlight, i.e. with radiation in the wavelength range from 280-650 nm.Particularly suitable light sources are HeCd, argon or nitrogen laserlight as well as metal vapour and NdYAG lasers with multiple frequency.Those skilled in the art will know that the appropriate photoinitiatorfor each selected light source must be chosen and, if necessary,sensitised. It has been found that the depth of penetration of theradiation into the polymerised composition and the processing rate aredirectly related to the absorption coefficient and the concentration ofthe photoinitiator. In stereolithography it is preferred to use thosephotoinitiators which generate the highest number of resulting freeradicals and make possible the greatest depth of penentration into thecompositions to be polymerised.

The invention further relates to a process for the production ofthree-dimensional objects from the novel liquid compositions bylithographic methods, especially by stereolithography, in which a layerof novel liquid composition is irradiated over the entire surface or ina predetermined pattern with a UV/VIS light source, such that within theirradiated areas a layer solidifies in a desired layer thickness, then anew layer of novel composition is formed on the solidified layer, whichis likewise irradiated over the entire surface or in a predeterminedpattern, and such that three-dimensional objects are formed from aplurality of solidified layers which adhere to one another by repeatedcoating and irradiation.

In this process it is preferred to use a laser light which is preferablycomputer-controlled.

The novel compositions are distinguished by low viscosity and hence goodprocessing properties. The green models obtained by precuring with laserlight and the fully cured objects have good mechanical properties,especially superior flexibility.

The novel compositions can be used typically as adhesive or coatingcompositions or as formulations for stereolithography or other methodsof model construction with photopoplymers.

If the novel compositions are used as coating compositions, clear andhard coats are obtained on wood, paper, metal, ceramic or othersurfaces. The coating thickness can vary over a very wide range and befrom c. 1 μm to c. 1 mm. Relief images for printed circuit boards orprinting plates can be produced from the novel compositions,conveniently by computer-controlled laser light of appropriatewavelength or using a photomask and a suitable light source.

It is preferred to use the novel compositions for the production ofphotopolymerised layers, especially in the form of three-dimensionalobjects which are formed from a plurality of solidified layers whichadhere to one another.

EXAMPLES I. Preparation of the Novel Acrylates and Methacrylates

I.1. Acrylate A: Diacrylate of2,2-bis(p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane

Method I: 100 g of2,2-bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane (preparedaccording to EP-A 22 073) having an epoxy value of 2.9 eq/kg aredissolved in 250 ml of toluene. Then 1 g of tetraethylammonium bromideand 0.2 g of hydroquinone m ether are added and the mixture is heated to80° C. A mixture of 22.98 g (0.32 mol) of acrylic acid and 0.17 g ofhydroquinone monomethyl ether is then slowly added dropwise. Thereaction mixture is kept at 80° C. until the epoxy value is less than0.1 eq/kg (c. 14 h). The reaction mixture is then cooled to roomtemperature and extracted with a 5% aqueous solution of NaHCO₃ and thenwith water. The organic phase is dried and concentrated first on arotary evaporator and then under a high vacuum.

Yield: 106.94 g (88.5%).

Method II: 0.2 g of di-tert-butyl p-cresol are added to 343.9 g of2,2-bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane (preparedaccording to EP-A 22 073) having an epoxy value of 2.9 eq/kg, and themixture is heated to 110° C. With stirring, a mixture of 72.06 g (1 mol)of acrylic acid, 0.56 g of Nuosyn Chromium® 5 % (fatty acid chromiumsalt in hydrocarbons, Durham Chemicals, GB) and 0.42 g of di-tert-butylp-cresol is added dropwise. The mixture is kept at 110° C. until theepoxy value is less than 0.1 eq/kg (c. 4 h). A brownish viscous resinhaving a double bond value of 2.38 eq/kg is obtained (88.5 % of theory).

I.2. Methacrylate B: Dimethacrylate of2,2-bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane

343.9 g of 2,2-bis[p-(3-butoxy-2-glycidyloxypropoxy)phenyl]propane(prepared according to EP-A 22 073) having an epoxy value of 2.9 eq/kgare reacted with 86.09 g (1 mol) of methacrylic acid by method IIdescribed above. The mixture is stirred at c. 110° C. until the epoxyvalue is less than 0.1 eq/kg (c. 4 h). A brownish viscous resin having adouble bond content of 2.26 eq/kg is obtained (87.2 % of theory).

I.3. Acrylate C: Diacrylate of2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)cyclohexyl]propane

100 g of 2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)cyclohexyl]propane(prepared according to EP-A 22 073) having an epoxy value of 2.48 eq/kgare reacted with 19.67 g (0.273 mol) of acrylic acid by method Idescribed above. The solution is stirred for 4 h at 80° C. The epoxyvalue is then 0.12 eq/kg. After extraction with a 5% aqueous solution ofNaHCO₃ and then with water, the organic phase is concentrated under ahigh vacuum.

Yield: 87.8 g (74.5%); Double bond value: 1.91 eq/kg (71.8% of theory).

I.4. Methacrylate D: Dimethacrylate of2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)cyclohexyl]propane

82 g of 2,2-bis[4-(3-butoxy-2-glycidyloxypropoxy)cyclohexyl]propane(prepared according to EP-A 22 073) having an epoxy value of 2.48 eq/kgare reacted with 19.2 g (0.223 mol) of methacrylic acid by method Idescribed above. The solution is stirred for c. 32 h at 80° C. The epoxyvalue is then 0.17 eq/kg. After extraction with a 5% aqueous solution ofNaHCO₃ and then with water, the organic phase is concentrated under ahigh vacuum.

Yield: 84.33 g (84.7%); Double bond value: 1.90 eq/kg (74.5% of theory).

I.5. Acrylate E: Diacrylate of2,2-bis[p-(3-phenoxy-2-glycidyloxypropoxy)phenyl]propane

50 g of 2,2-bis[p-(3-phenoxy-2-glycidyloxypropoxy)phenyl]propane(prepared according to EP-A 22 073) having an epoxy value of 2.7 eq/kgare reacted with 9.76 g (0.135 mol) acrylic acid by method II describedabove to give a viscous resin having a double bond value of 2.28 eq/kg(85.8% of theory).

I.6. Acrylate F: Diacrylate of2,2-bis[p-(3-cyclohexylcarbonyloxy-2-glycidyloxypropoxy)phenyl]propane

a) Preparation of2,2-bis[p-(3-cyclohexylcarbonyloxy-2-glycidyloxypropoxy)phenyl]propane(according to EP-A 22 073):

With stirring, 50 g (0.27 mol) of glycidyl cyclohexanoate, 30 g (0.135mol) of bisphenol A and 0.8 g of benzyltrimethylammonium bromide areheated to 110° C. When the exothermic reaction has subsided (rise intemperature to 140° C.), the reaction mixture is further stirred at 10°C. until the epoxy value is less than 0.1 eq/kg (2 h).

35 g (0.059 mol) of the resultant reaction product are reacted with 87 g(0.94 mol) of epichlorohydrin and 0.77 g of tetramethylammonium bromideby the method described in EP-A 22 073. After addition of 9.6 g (0.12mol) of 50% aqueous sodium hydroxide and removal of the water undervacuum, the product is isolated and dried.

Yield: 15.5 g (37%); Epoxy value: 1.90 eq/kg (74.5% of theory).

b) Preparation of the diacrylate:

12.97 g (0.27 mol) of2,2-bis[p-(3-cyclohexylcarbonyloxy-2-glycidyloxypropoxy)phenyl]propaneprepared according to a) are reacted with 1.8 g (0.025 mol) of acrylicacid by method II described above to give a viscous resin having adouble bond value of 1.84 eq/kg (78.3% of theory).

I.7. Acrylate G: Diacrylate of2,2-bis[p-(2-glycidyloxyhexoxy)phenyl]propane

a) Preparation of 2,2-bis[p-(2-glycidyloxyhexoxy)phenyl]propane(according to EP-A 22 073):

With stirring, 100.2 g (1 mol) of butyl oxirane, 114 g (0.5 mol) ofbisphenol A and 2.14 g of benzyltrimethylammonium bromide are heated to110° C. When the exothermic reaction has subsided (rise in temperatureto 115° C.), the reaction is further stirred at 110° C. until the epoxyvalue is less than 0.1 eq/kg (16 h).

85.52 g (0.2 mol) of the resultant reaction product are reacted with 296g (3.2 mol) of epichlorohydrin and 1.32 g of tetramethylammonium bromideaccording to the method described in EP-A 22 073. After addition of 33.6g (0.42 mol) of 50% aqueous sodium hydroxide and removal of the waterunder vacuum, the product is isolated and dried.

Yield: 87.2 g (80.6%); Epoxy value: 2.51 eq/kg (67.9% of theory).

b) Preparation of the Diacrylate:

100 g (0.31 mol) of 2,2-bis[p-(2-glycidyloxyhexoxy)phenyl,p4paneprepared according to a) are reacted with 15.85 g (0.22 mol) of acrylicacid by method II described above to give a viscous resin having adouble bond value of 1.87 eq/kg (64% of theory).

I.8. Acrylate H: Diacrylate of2,2-bis[p-(2-phenyl-2-glycidyloxyethoxy)phenyl]propane

a) Preparation of 2,2-bis[p-(2-phenyl-2-glycidyloxyethoxy)phenyl]propane(according to EP-A 22 073):

With stirring, 100 g (0.83 mol) of phenylethylene oxide, 94.7 g (0.415mol) of bisphenol A and 1.95 g of benzyltrimethylammonium bromide areheated to 110° C. When the exothermic reaction has subsided (rise intemperature to 115° C.), the reaction mixture is further stirred at 110°C. until the epoxy value is less than 0.1 eq/kg (5 h).

80 g (0.17 mol) of the resultant reaction product are reacted with 251.6g (2.72 mol) of epichlorohydrin and 0.9 g of tetramethylammonium bromideaccording to the method described in EP-A 22 073. After addition of 28.8g (0.36 mol) of 50% aqueous sodium hydroxide and removal of the waterunder vacuum, the product is isolated and dried.

Yield: 60.5 g (58.5%); Epoxy value: 2.56 eq/kg (78% of theory).

b) Preparation of the Diacrylate:

25 g (0.032 mol) of2,2-bis[p-(2-phenyl-2-glycidyloxyethoxy)phenyl]propane preparedaccording to a) are reacted with 4.6 g (0.064 mol) of acrylic acid bymethod II described above to give a viscous resin having a double bondvalue of 2.12 eq/kg (76.8% of theory).

II. Use Examples

Use of the novel diacrylates and dimethacrylates in formulations forstereolithography.

Example 1

49.85 g of acrylate A, 26 g of the dimethacrylate of ethoxylatedbisphenol A (SR 348, Sartomer), 14 g of trimethylolpropanetrimethacrylate (SR 350, Sartomer) and 6 g of phenoxyethyl acrylate (SR339, Sartomer) are mixed at c. 60° C. with 0.15 g of hydroquinonemonomethyl ether and 4 g of 1-hydroxycyclohexyl phenyl ketone. Theresultant homogeneous liquid formulation has a viscosity of 631 mPa·s at30° C. A moulded article (green mode cured from this formulation using aHe/Cd laser

(40 mJ/cm²) has a modulus of elasticity (DIN 53 371; green strength) of16.2 N/mm², a tensile strength σ_(max) (DIN 53 455) of 1.31 N/mm² and aflexural elongation ε (DIN 53 455) of 10.2%.

The green model is fully cured by irradiation for 30 minutes with UV/VISlight The moulded article then has the following properties:

modulus of elasticity: 1610 N/mm²

tensile strength σ_(max): 32.8 N/mm²

flexural elongation ε: 7.2%

Examples 2-10

Formulations of the components listed in Tables 1 and 2 are prepared andprocessed to three-dimensional objects as described in Example 1. Theproperties of the liquid formulations, of the green models and of thefully cured moulded articles are indicated in Table 2.

TABLE 1 Example 1 2 3 4 actylate A [g] 49.85 36.85 methacrylate B [g]49.85 methacrylate D [g] 48.85 dimethacrylate of ethoxylated bisphenol A26.0 26.0 6.0 [g] (SR 348, Sartomer) diacrylate of ethoxylated bisphenolA [g] 26.0 25.0 (SR 349, Sartomer) trimethylolpropane trimethacrylate(SR 350, 14.0 14.0 6.0 Sartomer) [g] trimethylolpropane triacrylate (SR351, 14.0 12.0 Sartomer) [g] phenoxyethyl acrylate (SR 339, 6.0 6.0 6.05.0 Sartomer) [g] 1-hydroxycyclohexyl phenyl ketone [g] 4.0 4.0 5.0 4.0N-vinylpyrrolidone [g] 5.0 hydroquinone monomethyl ether [g] 0.15 0.150.15 0.15 Viscosity η of the liquid formulation at 631 578 451 302 30°C. [mPa · s] Properties of the green models modulus of elasticity[N/mm²] 16.2 20.4 35.8 tensile strength σ_(max) [N/mm²] 1.31 1.56 2.70flexural elongation ε [%] 10.2 20.4 12.5 Properties of the fully curedmoulded articles modulus of elasticity [N/mm²] 1610 1734 1660 251.3tensile strength σ_(max) [N/mm²] 32.8 35.0 32.0 9.8 flexural elongationε [%] 7.2 4.1 5.0 11.0

TABLE 2 Example 5 6 7 8 9 10 acrylate A [g] 9.0 30.0 19.0 methacrylate B[g] 9.0 30.0 19.0 dimethacrylate of ethoxylated 29.0 29.0 5.0 5.0 29.029.0 bisphenol A (SR 348, Sartomer) [g] diacrylate of ethoxylated 20.020.0 bisphenol A (SR 349, Sartomer) polyethylene glycol 14.0 14.0 14.014.0 400 diacrylate [g] (SR 344, Sartomer) neopentylglycol diacrylate7.0 7.0 7.0 7.0 trimethylolpropane triacrylate 12.0 12.0 [g] (SR 351,Sartomer) phenoxyethyl acrylate [g] 1.0 1.0 5.0 5.0 1.0 1.01-hydroxycyclohexyl phenyl 5.0 5.0 5.0 5.0 5.0 5.0 ketone [g] aliphaticurethane acrylate [g] 35.0 35.0 23.0 23.0 25.0 25.0 (SR 9640, Sartomer,MG: 1300, viscosity at 60° C.: 18000 mPa · s) viscosity η of the liquid1490 1600 2250 2120 1010 925 formulation at 30° C. [mPa · s] Propertiesof the green models modulus of elasticity [N/mm²] 23.9 59.4 52.2 36.419.6 27.3 tensile strength σ_(max) [N/mm²] 3.7 3.8 3.7 3.9 2.9 3.3flexural elongation ε [%] 22.8 17.4 13.6 20.0 19.9 18.8 Properties ofthe fully curred moulded articles modulus of elasticity [N/mm²] 729 948772 1340 941 1102 tensile strength σ_(max) [N/mm²] 26.6 27.8 18.7 24.825.8 30.0 flexural elongation ε [%] 21.0 17.4 7.5 6.3 13.5 16.0

What is claimed is:
 1. A compound of formula (Ia) or (Ib)

wherein the substituents R₁ are each independently of the other hydrogenor methyl, R₂ is an unsubstituted C₁-C₂₀alkyl group or a C₁-C₂₀alkylgroup which is substituted by one or more than one substituent selectedfrom the group consisting of hydroxy, C₆-C₁₄aryl and halogen, anunsubstituted phenyl group or a phenyl group which is substituted by oneor more than one substituent selected from the group consisting ofC₁-C₆alkyl, hydroxy or halogen, or is a radical of formula—CH₂—OR₃,wherein R₃ is an unsubstituted C₁—C₂₀alkyl group or a C₁-C₂₀alkyl groupwhich is substituted by one or more than one substituent selected fromthe group consisting of hydroxy, C₆-C₁₄aryl and halogen, anunsubstituted phenyl group or a phenyl group which is substituted by oneor more than one substituent selected from the group consisting ofC₁-C₆alkyl, hydroxy and halogen, or is a C₂-C₆alkenyl group, aC₂-C₂0acyl group or an unsubstituted cyclohexyl-carbonyl group or acyclohexylcarbonyl group which is substituted by one or more than onesubstituent selected from the group consisting of C₁-C₆alkyl, hydroxyand halogen, Z is a group of formulae (IIa)-(IIe)

wherein Y is a direct bond, C₁-C₆alkylene, —S—, —O—, —SO—, —SO₂— or—CO—, and R₁ is hydrogen or methyl, and wherein the aromatic andcycloaliphatic rings of formulae (IIa)-(IIe) are unsubstituted orsubstituted by one or more than one substituent selected from the groupconsisting of C₁-C₆alkyl, chloro and bromo.
 2. A compound of formula(Ia) or (Ib) according to claim 1, wherein R₂ is preferably C₁-C₂₀alkyl,phenyl, C₁-C₂₀alkoxymethyl, phenoxymethyl orcyclohexylcarbonyloxymethyl.
 3. A compound of formula (Ia) or (Ib)according to claim 1, wherein R₂ is n-butyl, phenyl, n-butoxymethyl,phenoxymethyl or cyclohexylcarbonyloxymethyl.
 4. A compound of formula(Ia) or (Ib) according to claim 1, wherein R₂ is n-butoxymethyl.
 5. Acompound of formula (Ia) or (Ib) according to claim 1, wherein Z is agroup of formula (IIc) or (IIe).
 6. A compound of formula (Ia) or (Ib)according to claim 1, wherein Z is


7. A process for the preparation of a compound of formula (Ia) or (Ib)according to claim 1, which comprises reacting a diglycidyl ether offormula (III)

wherein R₂ and Z are as defined in claim 1, with acrylic or methacrylicacid.